Under dispenser containment system with integral penetration fittings and separate fitting support structure

ABSTRACT

An under dispenser containment system with integral penetration fitting and a fitting support structure separate from the sump. The containment system is adapted for use under fuel dispensers. The containment system comprises a double-walled sump with apertures and lips surrounding the apertures molded into the inner and outer walls. The containment system also comprises a fitting support structure that is not attached to the sump to allow replacement of the support structure without having to replace the sump.

FIELD OF THE INVENTION

The present invention relates to an under dispenser containment system (“UDC”) for use under a fuel dispenser such as the kind used to dispense gasoline, diesel or aviation fuel. The system includes quasi-integral penetration fittings and a shear valve support structure separate from the sump portion of the UDC. The UDC is double-walled and made of polyethylene.

BACKGROUND OF THE INVENTION

Fuel such as gasoline, diesel and aviation fuel is typically stored in large underground storage tanks (“USTs”) and transported by a pump through underground piping to the area below above-ground fuel dispensers. At that point, the underground piping makes a turn to run vertically upward toward the fuel dispenser. Typically, a shear valve is located near the base of the dispenser. The shear valve closes off the fuel pipe to prevent massive fuel leaks in the event that the fuel pipe above the shear valve is broken which can occur, for example, if the fuel dispenser is hit by a car.

Many jurisdictions, require the fuel to be secondarily contained to reduce the possibility of fuel leaking from the fuel handling equipment into the environment. Thus, UST's are typically double-walled with an inner wall that contains the fuel and an outer wall intended to contain any fuel that may leak through openings in the inner wall. Underground piping also is typically double-walled with an inner pipe that contains the fuel and an outer pipe intended to contain any fuel that may leak from the inner pipe. The interstitial space between the inner and outer wall of the UST and the underground piping may be monitored to detect leaks in either the inner or outer wall. Such monitoring may be accomplished by placing the interstitial space under vacuum and monitoring the vacuum pressure or filling the interstitial space with inert fluid and monitoring the level of the inert fluid. The underground piping typically is constructed from either fiberglass or polyethylene (“PE”). PE piping offers certain advantages over fiberglass piping in that PE is more flexible while fiberglass is more brittle. Fiberglass, however, is easier to bond with other materials making it easier to obtain solid connections that do not leak.

Under the fuel dispenser, the secondary containment is typically provided by an under dispenser containment (“UDC”) system. The shear valves are typically located within the sump portion of the UDC. The internal piping of the dispenser is located above the sump such that any leaks from the internal piping will fall into and be contained within the sump. Examples of UDCs are shown in U.S. Pat. Nos. 4,842,163, 5,246,044 and 5,301,722.

Historically, UDCs have presented several challenges. The piping that carries the fuel must pass through the UDC. In most UDC systems, the penetration apertures in the sump are cut at the installation site to allow the apertures to be placed in the proper locations with respect to the underground pipes. Cutting the apertures at the installation site increases the time and complexity of the installation. In addition, such penetrations are difficult to seal against leaks. Thus, the penetrations are usually located on the side of the sump rather than the bottom so that if the penetration is not sealed properly, no liquid fuel will leak through the penetration unless the liquid fuel fills the sump to at or above the level of the penetrations. If the underground piping in a fuel facility is made from fiberglass, many jurisdictions require a four-foot run of pipe from the exterior of the sump before a fitting may be placed on the pipe. Examples of such fittings might include an angled fitting to change the direction of the pipe or a straight connection to connect to a second length of underground pipe. If a four-foot run is required, the penetration is typically made in the side of the sump to avoid having to excavate to a depth of four feet below the bottom of the sump and run the fuel piping connecting to the USTs at an excessive depth.

One example of an attempt to deal with the propensity of such penetrations to leak is found in U.S. Pat. No. 5,246,044 (“Robertson”). Robertson discloses a fiberglass UDC with integral fiberglass couplings that penetrate the bottom of the UDC. The most common method of sealing a penetration fitting is a bulkhead style penetration fitting. One example of such a fitting is disclosed in U.S. Pat. No. 5,285,829. Use of bulkhead style fittings requires the UDC to be relatively large to allow the installer easy access to the interior of the UDC to install the portion of the bulkhead fitting located inside the UDC. With such larger UDCs, PE's flexibility presents a problem. If a relatively larger UDC is made of PE, the pressure from the surrounding dirt and concrete once the UDC is installed can cause the UDC to bend, buckle or collapse.

A second function of the UDC is to assist with providing support and bracing for the shear valves and internal piping of the dispenser. Typically, the support for the shear valves is connected to the sump portion of the UDC. For example, U.S. Pat. No. 4,842,163 discloses a “U” shaped brace that connects the shear valve to the side of the UDC. Robertson discloses shear valve support members connected to brackets attached to the UDC. One disadvantage of a connection between the shear valve and the UDC is that damage to the shear valve or internal piping, such as an impact by a car, usually results in damage to the UDC. That problem is particularly prevalent if the UDC is made of fiberglass because of its rigid properties. Thus, after such damage the entire UDC has to be replaced. Such replacement usually requires excavation, usually including breaking and re-pouring concrete surrounding the UDC.

SUMMARY OF THE INVENTION

The present invention presents a UDC system that overcomes many of problems addressed above. The sump portion of the UDC is double-walled and made of PE. The penetration apertures are pre-molded in the inner and outer walls at the bottom of the sump portion of the UDC. Lips are provided around the edge of the apertures in both the internal wall and the external wall. In the preferred embodiment, double-walled PE pipes are placed in the penetration apertures and fittings are applied that fuse the outer wall of the pipe to the lips around the aperture providing what is essentially an integral penetration fitting. In addition, the lip around the penetration aperture in the internal wall reduces the chance that liquid fuel will leak out of the interior of the UDC in the event of a fuel spill and a failure of the fusion fitting.

The exterior end of the penetration pipe is connected to the underground fuel piping. The interior end of the penetration fitting is connected to a shear valve. The provision of the penetration pipes already installed in the sump portion of the UDC means that the total size of the sump can be smaller than those currently in use as there is no need to have easy access to the interior of the UDC to install bulkhead style fittings. The smaller size allows the UDC to maintain structural integrity even though it is made from PE. The provision of the penetration pipes and smaller size also allows the sump portion of the UDC to be replaced without the need to break and repour concrete.

The UDC system also is provided with a support rack for the shear valves and internal piping that is independent from sump portion of the UDC system. Anchors for the support rack are embedded in the concrete next to the upper lip of the UDC. A collar is connected to the anchors. The shear valves are held by the collar. The combination of a PE sump and a shear valve support rack independent from the sump in the disclosed system provides important advantages over the current state of the art. In the event of trauma to the dispenser, such as the dispenser being struck by a car, the internal piping of the dispenser will likely be damaged along with the mechanism providing support for the shear valves. In the current state of the art, the shear valve support structures are integral with the sump portion of the UDC. Thus, damage to the shear valve support structure frequently causes damage to the sump requiring replacement of both the sump and the support structure. Sumps in current use typically have a relatively narrow opening in the top and a wider body to allow room for workmen to work inside the sump. That structure results in the sump having “shoulders” that are typically covered with concrete. Thus, replacement of the sump usually requires excavation including breaking and re-pouring concrete.

In contrast to the current state of the art, the support structure for the shear valves of the disclosed UDC system is completely independent from the sump portion of the UDC. In addition, the sump portion of the UDC is made of PE which is flexible. Thus, in the event of trauma to the dispenser and damage to the shear valve support structure, the support structure usually can be removed and replaced without the need to break and re-pour concrete. In addition, the flexible properties of the PE sump portion typically allow the sump to absorb any trauma by flexing and springing back into position without any damage to the sump. Finally, the disclosed sump has no “shoulders” but rather straight sides and a lip that is intended to be located at ground level. Thus, should the sump portion need to be replaced, the sump can be lifted out after cutting the bottom of the sump around the penetration pipes. A new sump with openings appropriately sized to accommodate the existing penetration pipes and attached portions of the previous sump may be lowered into the existing hole and the joints sealed by hand welding or other known method. Such replacement may be done without the need to break and re-pour the surrounding concrete.

The present UDC system presents an additional advantage over the state of the art. As discussed, conventional practice when installing a UDC is to drill the penetration apertures at the location of installation and to install penetration fittings, such as bulkhead fittings, to seal the penetration points. In the preferred embodiment of the present UDC system, the penetrations are pre-installed with PE double-walled pipes extending through the sump and downward from the bottom of the sump portion. The UDC systems may be delivered in a frame that may be buried. Thus, installation may involve simply excavating a hole of an appropriate size and dropping the UDC system including the support structure into the hole. The underground piping is connected to the double-walled penetration pipes of the disclosed UDC system with conventional fittings that are used to connect one piece of underground pipe to another such as elbow or angle fittings. Thus, the disclosed UDC system greatly simplifies the installation process and reduces the chances of human error during the installation resulting in savings of time and money. The double-walled PE pipes of the present UDC system are easily attached to underground piping made of PE. The flexible properties of PE make it a preferable material for underground piping as compared with fiberglass underground piping.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a fuel dispenser and a cut-away front view of one embodiment of the UDC system installed beneath the fuel dispenser;

FIG. 2 is a front view of one embodiment of the UDC system;

FIG. 3 is a side cut-away view of one embodiment of the UDC system along line 3-3 of FIG. 2;

FIG. 4 is a plan view of one embodiment of the UDC system;

FIG. 5 is a side cut-away view of one embodiment of the UDC system along line 5-5 of FIG. 4;

FIG. 6 is an enlarged detailed view of one embodiment of the penetration fitting as indicated in FIG. 5;

FIG. 7 is a perspective view showing one embodiment of the UDC system including the support structure installed in earth and concrete; and

FIG. 8 is a front view of a fuel dispenser and a cut-away front view of a prior art sump installed beneath the fuel dispenser.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In accordance with the preferred embodiment of the present invention, as shown in FIG. 1, the UDC system, indicated generally as 10, is shown installed beneath fuel dispenser 12. Support rack 14 is connected to anchors 16 by bolts 18. Anchors 16 are embedded in concrete 20 poured on top of earth 22. Sump, indicated generally as 24, rests on earth 22 and is encased in concrete 20. UDC 10 is installed so that lip 60 of sump 24 is approximately level with the top of concrete 20. Fuel pipes 26 connect to penetration pipes 28 that pass through penetration fittings 30. Shear valves 32 are connected to the upper end of penetration pipes 28 and connected to rack 14 by brackets 34. Additional views of the foregoing components of the UDC system are shown in FIGS. 2 and 3.

As shown in FIGS. 3 and 5, sump portion 24 has an outer wall 36 and an inner wall 38 creating an interstitial space 40 that may be monitored for leaks in walls 36 and 38.

As shown in FIGS. 3, 4 and 5, support rack 14 may comprise two main L-shaped beams running either side of shear valves 32. Support rack 14 is connected to anchors 16 by bolts 18. Shear valves 32 are connected to support rack 14 by brackets 34. In the event of damage to support rack 14, such as might occur should dispenser 12 be hit by a car, bolts 18 may be removed, brackets 34 disconnected and rack 14 replaced without the need to remove and replace sump 24.

FIG. 6 shows a detail view of a penetration fitting 30. Penetration pipe, designated generally as 28, has an inner wall 42 and an outer wall 44 defining an interstitial space 46 that may be monitored for leaks in walls 42 or 44. The outer wall 36 of sump 24 is formed into an annular lip 48 that surrounds an aperture in outer wall 36 through which penetration pipe 28 passes. Similarly, inner wall 38 of sump 24 is formed into an annular lip 50 that surrounds an aperture in inner wall 38.

Cuff 52 is placed over and contains lip 48 and penetration pipe 28 where penetration pipe 28 passes through the aperture formed by lip 48. Cuff 52 contains internal heating elements that, when activated, partially melt those portions of cuff 52 that contact the outer wall 44 of penetration pipe 28 and lip 48 forming a permanent sealed bond with outer wall 44 and lip 48. Similarly, cuff 54 is placed over and contains lip 50 and penetration pipe 28 where penetration pipe 28 passes through the aperture formed by lip 50. Cuff 54 contains internal heating elements that, when activated, partially melt those portions of cuff 54 that contact the outer wall 44 of penetration pipe 28 and lip 50 forming a permanent sealed bond with outer wall 44 and lip 50. The bonding of lip 50, cuff 54 and outer wall 44 provides a sealed interior bottom surface of sump 24 that will catch and hold any fuel that may escape from the shear valves 32 or internal piping of the dispenser. Furthermore, in the event cuff 54 fails to bond completely to lip 50 and outer wall 44 or such bond fails at some point in time, lip 50 provides some protection against leaks as any fluid would need to build up in the bottom of sump 24 to a height above lip 50 before such fluid could leak through the aperture defined by lip 50. In such an event, the fluid would still be contained within sump 24 in the interstitial space 40. Monitoring of interstitial space 40 by known means would alert interested parties to any failure at any point in penetration 30.

FIG. 7 shows the UDC system 10 installed in a typical fueling station environment and illustrates the convenient installation of the UDC system. Anchors 16 are partially embedded in concrete 20. Support rack 14 is connected to anchors 16 by bolts 18. Sump 24 is supported by support frame 56 and, after concrete 20 is poured, lip 60. To install UDC system 10, a hole is dug in earth 22 that is large enough and deep enough to accommodate sump 24, support frame 56 and the portion of penetration pipes 28 that extend below sump 24. Before and during installation, anchors 16 and connected support rack 14 may be held in place at the appropriate level with respect to sump 24 by bands 58 that connect anchors 16 to support frame 56. UDC system 10 and support frame 56 are lowered into the hole and penetration pipes 28 are connected to fuel pipes 26 by conventional means. The hole is then backfilled and concrete 20 is poured.

Should it become necessary to replace support rack 14, support rack 14 may be disconnected from anchors 16 by removing bolts 18. Shear valves 32 are disconnected from brackets 34 and support rack 14 may be removed and replaced.

With reference to FIG. 6, should it become necessary to replace sump 24, support rack 14 is removed as described above, an annular cut may be made in inner wall 38 around each penetration pipe 28. A second annular cut may be made in outer wall 36 around each penetration pipe 28. Once the penetration pipes 28 have been separated from the walls of sump 24, sump 24 may be lifted out. A new sump 24 with holes in its inner wall 38 and outer wall 36 sized appropriately to accommodate penetration pipes 28 may be dropped into the hole. Penetration pipes 28 may be connected to outer wall 36 and inner wall 38 with annular patches and hand welding.

As shown in FIG. 8, typical prior art sumps such as sump 64 have shoulders 62 that are covered with concrete 20 which must be removed and repoured if the sump 64 is to be replaced. The replacement of sump 24 and support rack 14 in the disclosed UDC system 10 may be accomplished without the need to break and re-pour the concrete 20 surrounding UDC system 10 which greatly simplifies the replacement process saving both time and money and allowing the dispenser 12 to be put back into service much more quickly than is possible in the case of prior art UDC systems. 

1. A sump for a under dispenser containment system comprising: an inner wall and an outer wall defining an interstitial space; at least one lip provided in said inner wall defining an aperture in said inner wall; at least one lip provided in said outer wall defining an aperture in said outer wall; and said lips and said apertures approximately aligned with respect to each other.
 2. A sump for a under dispenser containment system according to claim 1 further comprising: said inner wall having a bottom surface; said inner-wall lip located on said inner wall bottom surface; said outer wall having a bottom surface; and said outer-wall lip located on said outer wall bottom surface.
 3. A sump for a under dispenser containment system according to claim 1 further comprising said inner wall and said outer wall made from polyethylene.
 4. A sump for an under dispenser containment system according to claim 1 further comprising a pipe passing through said apertures; and the exterior of said pipe bonded to said lips.
 5. A sump for an under dispenser containment system according to claim 2 further comprising a pipe passing through said apertures; and the exterior of said pipe bonded to said lips.
 6. An under dispenser containment system comprising: a sump having a bottom face and at least one side face; said at least one side face defining an open top; a support rack for supporting and positioning one or more shear valves positioned such that at least some portion of the support rack extends across said open top; and said support rack not being connected to said sump.
 7. An under dispenser containment system according to claim 6 with said support rack further comprising at least one anchor for positioning and securing said support rack with respect to said sump.
 8. An under dispenser containment system according to claim 6 with said sump further comprising: an inner wall and an outer wall defining an interstitial space; at least one lip provided in said inner wall defining an aperture in said inner wall; at least one lip provided in said outer wall defining an aperture in said outer wall; and said lips and said apertures approximately aligned with respect to each other.
 9. An under dispenser containment system according to claim 8 with said sump further comprising: said inner wall having a bottom surface; said inner-wall lip located on said inner wall bottom surface; said outer wall having a bottom surface; and said outer-wall lip located on said outer wall bottom surface.
 10. An under dispenser containment system according to claim 6 further comprising said sump made from polyethylene.
 11. An under dispenser containment system according to claim 8 with said sump further comprising a pipe passing through said apertures; and the exterior of said pipe bonded to said lips.
 12. An under dispenser containment system according to claim 9 with said sump further comprising a pipe passing through said apertures; and the exterior of said pipe bonded to said lips.
 13. An under dispenser containment system comprising: a sump; said sump having an inner wall and an outer wall defining an interstitial space; said inner and outer walls having a bottom surface and at least one side surface; said at least one side surfaces extending approximately perpendicular from said bottom surfaces; the top edge of said at least one side surface of said inner wall defining a top opening of approximately equal size to said bottom surface of said inner wall; at least one lip provided in said inner wall defining an aperture in said inner wall; at least one lip provided in said outer wall defining an aperture in said outer wall; and said lips and said apertures approximately aligned with respect to each other.
 14. An under dispenser containment system according to claim 13 further comprising: a pipe passing through said apertures; and the exterior of said pipe bonded to said lips.
 15. An under dispenser containment system according to claim 13 further comprising: said inner-wall lip located on said inner wall bottom surface; and said outer-wall lip located on said outer wall bottom surface.
 16. An under dispenser containment system according to claim 15 further comprising: a pipe passing through said apertures; and the exterior of said pipe bonded to said lips.
 17. An under dispenser containment system according to claim 13 further comprising: a support rack for supporting and positioning one or more shear valves positioned such that at least some portion of the support rack extends across said top opening; and said support rack not being connected to said sump.
 18. An under dispenser containment system according to claim 17 with said support rack further comprising at least one anchor for positioning and securing said support rack with respect to said sump.
 19. An under dispenser containment system according to claim 14 further comprising: a support rack for supporting and positioning one or more shear valves positioned such that at least some portion of the support rack extends across said top opening; and said support rack not being connected to said sump.
 20. An under dispenser containment system according to claim 19 with said support rack further comprising at least one anchor for positioning and securing said support rack with respect to said sump. 